10 Reasons Why Your Chiropractic Insurance Claims Will Get Denied

Many times your insurance claims will be denied or rejected. This can fall under three categories:

-Coding mistakes

-Documentation mistakes

-Administrative mistakes

Why might your insurance claim get denied?  There are a plethora of reasons. If you do not agree with any of these reasons for denial as adjudicated by the insurance company, you can file an appeal supported by documentation.

1. The patient is no longer covered by the insurance policy

Confirm coverage for the date of service before treating a “no longer covered” denial as settled. UnitedHealthcare’s 2026 provider guide directs providers to check eligibility and benefits before providing care and states that possessing a physical ID card is not proof of eligibility. The same guide says checking benefits or eligibility does not guarantee payment or coverage in a specific amount; actual reimbursement depends on service dates, benefit terms and administrative requirements. Follow the instructions for the actual payer and claim.

Source: UnitedHealthcare 2026 provider guide, pages 13–14 and 129.

2. The plan did not cover the out-of-network service

Verify your participation in the member’s specific plan network and whether that plan includes nonemergency out-of-network benefits before assuming out-of-network care is covered at a lower tier. UnitedHealthcare’s 2026 provider guide notes that network participation can differ across commercial products in a local market and contrasts plans that provide out-of-network benefits with plans such as Choice, Select, Core Essential, EPO, Individual Exchange and UHC Complete that do not cover out-of-network services except for emergency care unless specifically approved. Where an out-of-network exception or prior approval is sought, follow the payer’s process and check the actual plan terms and remittance before billing or appealing.

Source: UnitedHealthcare 2026 provider guide, pages 30–35, 51 and 85.

3. A lower level of service was deemed more appropriate

Compare the billed CPT or HCPCS code against the clinical record for that date of service before refiling or appealing. UnitedHealthcare’s 2026 provider guide notes that when documentation does not support the code reported, a different code may apply under code criteria, and describes billing a higher level of service than was provided as upcoding. For Medicare chiropractic manipulative treatment (CPT 98940, 98941 and 98942), CMS’s chiropractic documentation checklist requires each visit record to identify the specific spinal regions and levels manipulated and lists failure to document all treated spinal regions as a common denial reason. Submit a corrected claim if an inaccurate code was billed, or include the visit documentation when appealing a level-of-service reduction or denial.

Sources: UnitedHealthcare 2026 provider guide, pages 136–137 and 177; CMS Medicare documentation checklist for chiropractic doctors (MLN1232664), pages 3–5.

4. There was incomplete claim information

Check the claim response for the specific missing or invalid information before choosing the next step. For example, UnitedHealthcare’s 2026 provider guide lists member and subscriber details, payer ID and provider identifiers among the information needed for a complete claim. It directs providers to check clearinghouse reports and rejection communications when a claim is not reflected in its portal, and to correct a rejected claim before submitting it again. If the claim has already been accepted and is still processing, the guide says not to submit a second claim for the same services. Follow the instructions for the actual payer and claim status.

Source: UnitedHealthcare 2026 provider guide, pages 136–137.

5. The diagnosis and procedure codes were not linked correctly

Check that every ICD-10-CM diagnosis code is reported to the required specificity and linked to the matching service line. The NUCC 1500 Claim Form Reference Instruction Manual states that Item 24E (Diagnosis Pointer) must enter the reference letter (A–L) from Item 21 to relate the date of service and procedure performed to the primary diagnosis for that line, with the primary reference letter listed first and no ICD-10-CM code entered directly in Item 24E. UnitedHealthcare’s 2026 provider guide likewise requires claims to communicate the primary diagnosis for each service line, and CMS Medicare Coverage Database Article A56273 requires Medicare chiropractic claims to list the precise spinal subluxation level (M99.00–M99.05) as the primary diagnosis and the neuromusculoskeletal symptom or condition necessitating treatment as the secondary diagnosis.

Sources: NUCC 1500 Claim Form Reference Instruction Manual (v13.0), page 39; UnitedHealthcare 2026 provider guide, page 138; CMS Medicare Coverage Database Article A56273.

6. The provider’s service was deemed medically unnecessary

Review the payer’s clinical policy and the visit record before appealing a medical-necessity denial. Under CMS Medicare Coverage Database Article A56273 and CMS’s chiropractic documentation checklist (MLN1232664), Medicare covers chiropractic manipulation (CPT 98940, 98941 and 98942) only for active or corrective treatment of acute or chronic spinal subluxation billed with the AT modifier; once maximum therapeutic benefit is reached and further clinical improvement is not expected, ongoing maintenance therapy is not considered medically necessary, and the AT modifier alone does not establish medical necessity if the medical record does not support active care. Commercial policies also require documented functional improvement: Aetna Clinical Policy Bulletin 0107 requires a written plan of care with measurable goals and documented clinical improvement for ongoing care, and UnitedHealthcare’s 2026 provider guide notes that clinical medical-necessity denial notices outline the appeal process.

Sources: CMS Medicare Coverage Database Article A56273; CMS Medicare documentation checklist for chiropractic doctors (MLN1232664), pages 3–4; Aetna Clinical Policy Bulletin 0107; UnitedHealthcare 2026 provider guide, pages 104–109 and 258.

7. Required prior authorization was not obtained

Check whether prior authorization, notification or a referral was required for that service and plan, and whether any required approval was on file for the date of service. UnitedHealthcare’s 2026 provider guide distinguishes advance notification from prior authorization, states that required notification does not mean a service is covered, and says giving notification or receiving prior authorization is not a guarantee of payment unless required by law or Medicare guidelines. Follow the instructions for the actual payer and claim; do not assume every plan uses the same authorization process.

Source: UnitedHealthcare 2026 provider guide, pages 13 and 87–89.

8. There were multiple codes used when they should have been included in a bundled service

Check whether the billed CPT or HCPCS codes are combined under national correct coding edits or the payer’s reimbursement policies for the same date of service. UnitedHealthcare’s 2026 provider guide defines unbundling as billing each component of a service when one comprehensive code is available, states that it applies coding edits based primarily on CMS’s National Correct Coding Initiative (NCCI) and Outpatient Code Editor (OCE), and notes that missing or misused modifiers can cause claim delays or denials. CMS’s Medicare Claims Processing Manual (Chapter 5) similarly directs providers to append NCCI modifiers only under current coding instructions. Review the remittance advice and the applicable NCCI edit or payer reimbursement policy before submitting a corrected claim or reconsideration.

Sources: UnitedHealthcare 2026 provider guide, pages 128, 137, 140, 151, 177 and 393; CMS Medicare Claims Processing Manual, Chapter 5, Section 10.3.

9. The benefit was not covered by the insurance policy

Check the member’s benefit plan document and applicable payer coverage rules to confirm whether the specific service is covered, limited or excluded under that plan. UnitedHealthcare’s 2026 provider guide states that the member’s benefit plan document—such as the Summary Plan Description, Schedule of Benefits or Certificate of Coverage—identifies which services are covered, excluded or subject to limitations and supersedes general payer policies when they conflict. Under Original Medicare, CMS coverage article A56273 states that all services other than manual manipulation of the spine to treat a spinal subluxation are excluded when ordered or performed by a Doctor of Chiropractic. Verify the rules for the actual payer, plan and service before submitting or appealing.

Sources: UnitedHealthcare 2026 provider guide, pages 88 and 98; CMS Medicare Coverage Database Article A56273.

10. A pre-existing-condition exclusion was applied — check the plan type

Do not assume this is a valid denial reason for every health plan. HealthCare.gov states that all Marketplace plans must cover treatment for pre-existing medical conditions; grandfathered individual plans are an exception to that protection. Check the specific plan and denial notice before deciding how to challenge an exclusion. Sources: HealthCare.gov: pre-existing conditions.

Medicare rules to check first when a chiropractic claim is denied

The 10 reasons above apply to any payer. Medicare also has rules that apply only to chiropractic claims. When a Medicare chiropractic claim is denied, compare the claim and the visit record with these eight points before you decide on the next step. Each one is explained with its CMS source in our Medicare codes and modifiers cheat sheet.

• The AT modifier is missing. Medicare requires the AT modifier on CPT 98940, 98941 and 98942 for active or corrective treatment of acute or chronic subluxation. Claims without AT are treated as maintenance therapy and denied. See tip 44 on the AT modifier.
• The record does not support active treatment. Do not use AT for maintenance therapy. AT alone does not prove the service was reasonable and necessary: the medical record has to support active or corrective treatment.
• The line was billed with the GZ modifier. Medicare contractors automatically deny claim lines submitted with GZ. GA and GZ on the same service make the line unprocessable. GA is used with a signed Advance Beneficiary Notice (ABN) when the chiropractor bills with AT but believes Medicare is likely to deny the service as not medically necessary.
• The service is not spinal manipulation. CPT 98943 (manipulation of extraspinal regions) is not covered by Medicare. Exams, X-rays, physiotherapy, traction, supplies and similar services are excluded from Medicare coverage when ordered or performed by a chiropractor.
• The diagnosis codes are in the wrong order. The subluxation, at its precise level, is listed first on the claim. The neuromusculoskeletal condition that made treatment necessary is listed after it and coded to the highest level of specificity.
• The initial treatment date is missing. The date of the initial treatment, or of the exacerbation of the existing condition, must be entered in Item 14 of the CMS-1500 claim form.
• The subluxation is not documented. Medicare accepts an X-ray taken within 12 months before or 3 months after the start of treatment, or a physical exam that documents at least 2 of the 4 PART criteria (pain, asymmetry or misalignment, range of motion abnormality, tissue tone changes). One of the two must be asymmetry or misalignment, or range of motion abnormality.
• More than one manipulation was billed for the same day. Medicare typically pays for only one chiropractic manipulation per patient per day. More than one may be covered if medically necessary.

Sources: CMS MLN1232664, Medicare Documentation Checklist and Guidelines for Chiropractic Doctors; CMS Billing and Coding: Chiropractic Services, article A56273; Medicare Benefit Policy Manual, Chapter 15, Section 240.1.3; Medicare Claims Processing Manual, Chapter 12, Section 220; Medicare Claims Processing Manual, Chapter 23, Section 20.9.1.1. Commercial and Medicare Advantage plans set their own rules, so check the plan’s policy and the denial notice.

Denial codes on your remittance that match these 10 reasons

When a payer denies or reduces a chiropractic claim, the remittance advice (ERA or EOB) shows a Claim Adjustment Reason Code (CARC). X12 maintains the official Claim Adjustment Reason Codes list. The codes below are the ones whose official descriptions match the 10 reasons above. The exact code a payer sends depends on the payer and the claim, so always read the code and any remark code on your own remittance.

Two more codes are worth knowing: CARC 4 (The procedure code is inconsistent with the modifier used.) and CARC 29 (The time limit for filing has expired.). Once you know the code, see the steps under “What to do after a chiropractic claim is denied” below.

Rejected or denied? And what CO and PR mean in front of a denial code

Not every unpaid chiropractic claim is a denial. For Medicare, a claim that is returned as unprocessable because information is incomplete or invalid is not denied and has no appeal rights, according to the Medicare Claims Processing Manual, Chapter 1 (section 80.3.1). The provider is told what the error is and how to correct it before sending the claim again. A denied claim is different: the payer processed it and decided not to pay all or part of it. That is when the steps under “What to do after a chiropractic claim is denied” below apply. Other payers set their own rules, so read the notice that comes with the claim.

On a remittance advice, each adjustment can carry three kinds of codes: a group code, a Claim Adjustment Reason Code (CARC) and a Remittance Advice Remark Code (RARC). CMS explains on its remittance advice page that group codes assign financial responsibility for the unpaid portion of the claim balance. So “CO-50” means group code CO with reason code 50 from the table above. X12 lists four claim adjustment group codes:

Check the group code before you bill a patient or write off a balance: the same reason code can come with a different group code on a different claim.

What to do after a chiropractic claim is denied

Start with the denial reason on the remittance advice or EOB. If the claim was denied because of a coding or data error, such as a missing modifier, a wrong diagnosis pointer or incorrect patient information, a corrected claim is usually the faster fix. If the claim was billed correctly and the visit documentation supports it, file an appeal under the payer’s process.

For Medicare Part B claims, CMS describes five appeal levels (MLN006562, September 2025):

1. Level 1 – Redetermination by your Medicare Administrative Contractor (MAC): file within 120 days of receiving the initial determination (form CMS-20027 or a written request). MACs generally decide within 60 days.
2. Level 2 – Reconsideration by a Qualified Independent Contractor (QIC): file within 180 days of receiving the redetermination notice (form CMS-20033).
3. Level 3 – Office of Medicare Hearings and Appeals (ALJ hearing or on-the-record review): file within 60 days of the QIC decision; a minimum amount in controversy applies and is adjusted each year.
4. Level 4 – Medicare Appeals Council review: file within 60 days of the OMHA decision.
5. Level 5 – U.S. District Court judicial review: file within 60 days of the Council decision; a minimum amount in controversy applies.

CMS also advises making every appeal request in writing, filing on time with the right entity, including copies of earlier decision letters, and sending all relevant supporting documents with your first appeal request. For a chiropractic medical-necessity denial, that usually means the visit note for the date of service, the treatment plan and the documentation of the spinal regions treated.

Commercial plans set their own appeal steps and deadlines, so check the denial notice and the payer’s provider manual before filing.

Source: CMS MLN Booklet MLN006562, Medicare Parts A & B Appeals Process (September 2025).

Check whether the issue needs a corrected claim, reconsideration or appeal.

Use the payer’s instructions and the deadline that applies to the plan and claim. For example, UnitedHealthcare’s provider guide distinguishes a corrected claim from a request to reconsider a payment or denial. Include the documentation relevant to the stated reason; resubmitting the same claim is not a substitute for the required dispute process. Sources: UnitedHealthcare 2026 provider guide.

If denial follow-up is taking too much of your week, see our chiropractic billing services or read about insurance recoupments.

Related reading: chiropractic billing tips on claim corrections, payer instructions and follow-up.